1. Field of the Invention
The present invention relates to the radiotelephony field.
It finds a general application in the location of mobile subscribers in a radiotelephone installation, and more particularly in a radiotelephone installation of the MSG (Mobile Special Group) type.
2. Description of the Related Art
Generally speaking, a radiotelephonic process for locating mobile subscribers comprises the following steps:
a) provision of at least one mobile telephone set for a predetermined mobile subscriber having a predetermined mobile subscriber identity, the said mobile telephone set being intended to be in intercommunication with fixed telephone sets connected to a fixed telephone communication network; PA1 b) provision of a plurality of geographic location zones, each having radio coverage from at least one base station, and each location zone having a predetermined identity; PA1 c) provision of recording means connected to the base stations and containing data relating to the identity of the subscriber and to the identity of the current location zone of the mobile telephone set; PA1 d) at the recording means, creation of a profile for the mobile subscriber composed of a list of couplets (Zi, fi) where Zi is a location zone identity and fi represents a function with at least one predetermined operand giving the probability of locating the subscriber in the location zone Zi at a given instant, and storage of the said profile thus created in the recording means; PA1 e) after storage of the profile, in response to a telephone call request directed to the mobile subscriber, interrogation of the recording means in order to select from the profile in accordance with the operand at least the location zone identity assigned the highest probability, and the broadcast of a search message in the location zone with the identity thus selected; PA1 f) in the event of positive location, at the mobile telephone set, reception of the search message and, in response, the establishing of radiotelephone intercommunication with the caller, while in the event of negative location, the broadcasting of the search message in another location zone, if necessary (JP-A-62 299 123; JP-A-31 31 131). PA1 i) the construction, from the start and end times of the various daily chronological periods in the first work file, of a list of successive weekly chronological periods, the first weekly chronological period having a start of value greater than or equal to 00:00 and an end corresponding to the end of the daily chronological period having the smallest value among those of the end times of the daily chronological periods of the first work file, and the last weekly chronological period having an end of value less than or equal to 23:59 and a start corresponding to the start of the daily chronological period having the largest value among those of the start times of the daily chronological periods of the first work file, the daily identity of the location zone of the corresponding daily chronological period being assigned to each weekly chronological period; PA1 ii) by searching the data of the first work file, obtaining the different location zone daily identities assigned for each weekly chronological period thus constructed; PA1 iii) the counting of the recurrence of each location zone daily identity for each weekly chronological period; and PA1 iv) the ordering of the different location zone daily identities according to their recurrence for each weekly chronological period. PA1 the construction, in the mobile telephone set operating mode, of a second work file, substantially similar to the first work file, and containing data relating to the daily chronological periods and to the location zone daily identities recorded in the recording means during a second predetermined period which follows the first observation period and not recorded in the first work file during the said first observation period; and PA1 the processing of these new data in accordance with steps i to iv in order to update the profile.